Lamp changing apparatus



Oct. 7, 1941. J, R. MacKAY 2,258,575

LAMP CHANGING APPARATUS Filed Feb. 15, 195B 2 Sheets-Sheet l &

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A; ATTORNEY 5% II. n VIII Ila Oct. 7, 1941. R MacKAY 2,258,575

LAMP CHANGING APPARATUS Filed Feb. 15, 1938 2 Sheets-Sheet 2 B y M 7F. 2332.?

1 ATTORNEY Patented Oct. 7, 1941 UNITED STATES PATENT OFFICE LAMP CHANGING APPARATUS Application February 15, 1938, Serial No. 190,565

12 Claims.

This invention relates to apparatus for automatlcall replacing electric lamps which have failed. The invention has been made especially with the idea of providing an improved lampchanging apparatus for fixed light or flashing "light signal devices which are required to operate tor long periods of time without attention.

More particularly, the invention aims to provide such a lamp-changing apparatus operated "by alternating current motor means which is' comparativel simple and inexpensive in construction and very reliable in operatiomwhlch has no relays or delicate electric contacts, which moves the new lamps into operative position rapidly and positions 'them accurately, and which effects the replacement operation smoothly, avoiding'harmful jarring.

To these ends, in an apparatus according to the invention, themeans iormovinga plurality of lamps one after another into an operative position to replace units which have failed, comprises alternating current motor means which has a winding electrically associated with the lamp circuit in series with the positioned lamp "whereby when a normally operating lamp is in -operative position operation of the motor means to produce lampechanging movement is preventedyand which-when through failure ottherpositioned lamp the flow of current through said winding is stopped or sufliciently reduced does produce-such movement.

"Another object of the invention is to provide apparatuswhioh may have a large reserve lamp 'capacity'ina comparatively limitedspace. Other objects-will appear from-the.followingvdescription.

-A fullunderstanding 'oftheinvention can best begiven by adetaileddescitiption of apparatus "embodying -the invention or .features thereof in the iormsnow considered best, and such a description will now be given in connection with .theaccompanying drawings illustrating such ap- .paratus.

lIn-said drawings:

Fig. '1 is .a simplified diagrammatic view of belt looking from the left of Fig. 2 and showing the carrier with the disc l8 removed and without the carrier belt thereon;

Fig. 3 is a diagrammatic view of a modified form of motor;

Fig. 4 is a view similar to Fig. l but showing a modified embodiment of features of the inven tion; and

Fig. 5 is a diagrammatic view of a further modified apparatus embodying features of the invention.

"Referring to the drawings, and firstto Figs. 1 13021), the lamp-changing apparatus shown comprises a lamp-carrying 'belt formed of a plurality of flat metal plates [0 pivotally connected at their :edges. The carrier belt may be placed folded, as-shown, in a suitable rmagazine II, or the carrier-belts may be supplied folded or otherwise suitably stored in suchmagezzines. The end of the belt is placed about a rotary support l5 and may have a weight W on or attached to the end plate-to exert a downward force to help hold the .oarrier-belt in proper position on the rotary support. The :rotary support, which as shown in Fig. 2-is mountedon a vertical support .lB, is formed of two spaced discs l1 and Hl'of Bakelite -or other insulating material, a metal disc 19 attachedto the disc l1, and fourmetal rods 4.0 extending between the .discs l8 and I9 and equally .spaeedimm theaxis of rotation of the support 'and'equally-spaced irom each other. The discs J] and 48 are rotatably mounted on a metal axlelA extending from and insulated from the support l6,and.the.metal disc H! has a central opening ofsuch size that .it does not make contact with the-axle.

The carrier .belt is supported .on the rods 20 and these rods arespaced according to thelength of the carrierplatesso that thelcarrier belt will turn about the support with itsplates successively bridging ,th space between adjacent supporting rods. Each of the carrier plates carries an electric .lamp 25, and as the carrier belt is advanced by rotation of the support I5, the lamps will be successively moved to operative position, .WhiChJn the apparatus shown is the uppermost position in Figs. 1 and 2, a. quarter rotation of the support I5 serving to move one lamp out of position and the next lamp on the carrier belt into position. The rotary support is provided with pins 15 extending from plates 21 carried by the carrier supporting rods 20, these pins projecting sufficiently to enter corresponding perforations 26' in the carrier plates to give good traction and insure accurate positioning of the carrier plate on the support.

Each carrier plate is provided with a lamp socket such that the side of the lamp base will be electrically connected with the carrier plate. The lamps shown are of the kind having a prefocused base and are mounted on the carrier plates so that the base extends through the carrier plate. Whatever type of lamp is used, the sockets on the plates will be such that the contact terminal at the end of the base of the D- sitioned lamp will engage a flexible contact strip or brush 30 on the axle 24. Connection will thus be made to one contact terminal of the positioned lamp through the axle 24, and connection to the other terminal of the positioned lamp is made from the disc [9 through the supporting rods 20 and the carrier plate.

The disc ll of insulating material has four indexing contacts 3|, most desirably of rare metal, set below the surface of the disc in radial grooves 32 in its outer face, the contact piece extending through the disc I1 and being conductively connected to the metal disc H, as shown in Figs. 2 and 2a. The contacts 3| and grooves 32 are equally spaced circumferentially of the disc. A contact 33 carried by a spring 34 bears against the disc H and is shaped and positioned so that when a lamp has been moved into operative position the contact 33 will enter one of the grooves 32 and engage the contact 3| therein to close the lamp circuit. As the disc begins to turn when the carrier is moved to position a new lamp, the contact 33 by its engagement with the side of the groove is immediately pushed away from contact 3| and out of the groove, and then rides on the face oi the disc until another lamp has been moved into position, whereupon it makes engagement with the next contact 3| to complete again the lamp circuit.

In Fig. 1. for convenience in diagrammatic,

illustration, the disc i1 is shown as having peripheral notches in which the contacts 3| are located, and the contacts are shown as connected to a ring from which connection to the positioned lamp is indicated by line a.

The carrier support I5 is turned for removing a burned out or defective lamp and bringing a new lamp into operative position by an alternating current motor 40. This driving motor as shown is an induction motor of the shaded pole type having a shunt field winding 4| connected across the feed line A-B, and having ring type shading coils 42 and 42' on split portions 43 and 43' of the motor poles which with the field winding normally set up a rotating magnetic field to rotate the motor armature 44 in the direction to give the desired lamp-changing movement to the rotary support IS. The motor has also wound shading coils 4B and 46' on portions 41 and 41' of the motor poles facing the portions 43 and 43' respectively. These auxiliary shading coils 46 and 46' are connected in series with each other and with the positioned lamp, the lamp circuit being from side A of the feed line by conductor 11 to the axle 24, thence throu h the positioned lamp to the contact spring 34 and thence by conductor c coil 46. conductor 11, coil 4-5 and conductor e to the side 13 of the feed line. With a properly functioning lamp in correct operating position. therefore, the auxiliary windin s 46 and 46' will be normally energized from the feed line.

These auxiliary windings are so connected or phased to the current source that when so energized they exert a shading effect which tends to create a rotating field opposite to that produced by the shading coils 42 and 42' suiiiciently powerful to prevent the motor from rotating and turning th lamp support l5. Therefore, when a lamp is properly positioned and functioning in the normal manner, the armature of the driving motor remains stationary, but when the positioned lamp burns out or the current through it becomes from any cause sufiiciently less than normal so that the flow of current through the auxiliary coils 45 and 45 is stopped or sufliciently reduced, the neutralizing effect of the auxiliary shading coils is removed and the motor operates to turn the support l5 until a new lamp has been moved into operating position, whereupon the normal current through the lamp circuit again energizes the auxiliary coils 46 and 46' and stops the motor. Due to the damping or braking action in the motor when the auxiliary coils are normally energized, the motor is stopped quickly and there is no tendency for the lamp-changing mechanism to overrun. In the event that the lamp moved into position is a dead lamp, the motor will continue to operate until a working lamp has been positioned. As the lamp circuit is opened between contacts 3| and 33 at the beginning of the lampchanging movement of the carrier i5 and closed again only when the disc has made a full quarter turn to permit the contact 33 to engage the next contact 3|, there can be no motor stopping flow of current through the auxiliary shading coils until the new lamp has been moved all the way to its operative position.

Any suitable driving mechanism may be provided between the motor shaft 48 and the carrier support l5. As shown, the carrier support is driven by a pinion 45 on the motor shaft which engages gear teeth formed on the periphery of the disc ll of the carrier support. In order to prevent reverse movement of the motor, a ratchet wheel 50 is provided on the motor shaft, engaged by a pawl 5|. If for any reason, such as the use of a lamp of increased wattage, the flow of current through the lamp circuit should be so large that the effect of the auxiliary windings would tend to cause the motor to rotate backwards, the pawl and ratchet detent will prevent any backward rotation. The use of a detent for this purpose avoids recourse to a shunt across the auxiliary windings. Reduction gears shown diagrammatically at 52 are interposed in the motor shaft, and a clutch 53 is desirably provided to permit the carrier support to be turned manually in either direction when desired without turning the motor armature.

In the motor shown in Fig. 3, the pole portions 43 and 43', instead of being provided with ring type shading coils as in Fig. l, are provided with wound shading coils 55 and 55' which are connected in series in a closed circuit in which a variable resistance 56 is interposed. The resistance arm 51 is set in accordance with the size of the lamps that are to be operated so that the motor armature 44 will not turn until the lamp burns out or the current through it decreases to a predetermined minimum.

In the modification shown in Fig. 4, two induction motors are provided which tend to turn the driving shaft 48 in opposite directions, one of hes the driving motor, turning the shaft when the lamp burns out and the other one stopping the driving motor and shaft when a new lamp arrives at its operating position, and so long as escapes the positioned lamp functions normally; also, .the 'apparatusis a flashing light apparatus, a .current interrupter being provided whereby an intermittent current is supplied to the lamp -circuit and also to the field winding of the driving :motor when a normally functioning lamp is in operating position.

The driving motor 60 is an induction motor "having a field winding GI and poles -62 with shading coils 63 to cause the armature M to turn the shaft 48, and thereby the carrier sup- .port 15,111 the proper direction to move a lamp .into operatingposition. The stopping motor 65, which is also an induction motor, is most desirably smaller than the driving motor and has its :armature 56 connected through a reduction gearing Blto the'driving shaft 48. Its shading poles 8 are ,provided with shading coils $9 and its armature tends to turn in the opposite .direction -.to that of the armature of motor.

.The field winding III of the stopping motor -is connected in series in the lamp circuit, the connection being by conductor y from the side A =of the feed line to one end of the field Winding and .from the other end of thefield winding through conductor h, contact spring 34 and contact 3| of .disc I] to the positioned lamp,=and from the lamp .through conductor b to side B of the feed line, the .disc l1 operating the contact spring 34 to open the lamp circuit at the start of a lampchanging movement of the carrier support l5 .and to close .the lamp circuit again only when a. new lamp has been moved into operative posi .tion.

The apparatus of Fig. 4 is a flashing light apparatus, the current supplied to the lamp circuit from the feed line A-B being converted into an intermittent current by means of suitable current-interrupting mechanism comprising, as shown, a program wheel H driven by anysuitable means and an interrupter 1.2 operated by the ,program wheel to cause regular or irregular currrent impulses as determined by the arrangement of the teeth or cam projections of the program wheel, which as shown has one such projection .for closing the circuit for ashort interval .once .I'or eachrotationof the wheel. The field winding :of thedriving motor is also connected across .the feed .line beyond the current interrupter so that the same intermittent current will be supplied to the driving motor as is suppliedto the lamp and to the stopping motor. This is'necessary as otherwise the driving motor would opcrate during the intervals when no current was flowing in the lamp circuit, during which 'intervals the stopping motor would be inactive.

If, however, the driving motor were dependent .on the intermittent current for itslamp-changvirig operation so that the rapidity of lamp change depended on the periodicity of current impulse, the movement of the lamp carrier would be comparatively slow and theperiod of=change during which no lamp was flashing might be suificient to cause trouble. Means are provided, therefore,

whereby when, on failure of the positioned lamp,

the carrier support is first moved by the driving motor energized by the intermittentcurrent, the current interrupter is shunted to permit current to-be supplied continuously to the driving motor from the feed line until a new lamp has been .moved into operative position. For this purpose, a spring contact is provided in position to be moved by the contact spring 34 when the latter is forced out of a groove 32 of the disc Flat the beginning of the lamp changing movement. -75

When .so moved by the contact spring 84 the spring contact I5 engages a contact 16, thereby shunting theinterrupter and establishing a circuit through conductors i and k whereby current isxcontinuously supplied to the driving motor so that it operates continuously until a new lamp has been positioned. If the lamp moved into position is a dead lamp, the motor will operate on the intermittent current until the contact :33 carried by the spring 34 is again forced out of the groove of the disc I1 and circuit again clrmed between contacts 15 and 16 for continuous supply of current .to the motor.

It will be understood that with any of the illustrative -forms of motors shown the current supplied to the lamp and to the motor coils may be :an intermittent current for producing a flashing signal light, and in any such case means such asabove described or other suitable means should desirably be provided for causing current to .be supplied to the driving motor continuously during .theJamp-changing operation of the motor. Also, the two-motor motor means of Fig. 4 may, obviously, :be used in a steady, or fixed, light apparatus.

Fig.4 shows, a1so,:a different sort of container or'magazine for the lamp carrier belt. As here shown. a support BI is provided in this magazine around which the carrier belt with the lamps "thereon may be wound.

In the modification shown by Fig. 5, the motor .90 is an induction motor having split poles and shading coils similar to the motor of Fig. 1 and amain field winding 9| connected to the feed line AB with resistance 92 in series with it. An auxiliary field winding opposing the winding :9! is provided andzis connected in series in the lamp circuit. This auxiliary field winding consists most desirably of a few turns of heavier wire andjs opposite in electromagnetic effect to the 'main field winding and so proportioned that its field .will .be suilicient to prevent rotation when .a lamp of minimum wattage is in series with it. Il'he purpose of the resistance 92 is to prevent excessive heating of the main field winding which wouldotherwise result from the increased current flow through the winding due to its decreased impedance caused by the closely placed auxiliary field winding.

The lamps .25 are mounted on a rotary carrier -84. As the lamps are successively moved into operative position, the side contact of the positioned lamp is connected with a stationary contact'95 connected to one side of the supply cir- .cuit A-B, and .the bottom contacts of all the lamps on the carrier are connected to a rotating contact ring 96 against which bears a brush .connected'to the auxiliary winding 93 from the other end of which there is a connection to .the other side of the supply circuit.

The operation of this apparatus of Fig. 5 is similar to that of the others in that when nor- =mal current is passing through the positioned lamp the field produced by the auxiliary winding 93 prevents the field produced by the main :windingSl from causing rotation of the motor .armature. but when the lamp circuit is opened or the current through the lamp and through coil 83 is toosmall, due either to burning out or deterioration of the lamp, the motor operates .until the carrier has been turned to bring the .next lamp to its operating position.

In the apparatus of Figs. 4 and 5, a ratchet wheel and pawl as shown in Fig. 1, or other suitable detent device, should, most desirably, be

provided for preventing backward rotation of the driving shaft, and suitable reducing gearing should also be provided between the driving motor and the lamp carrier, and a clutch may be provided as in Fig. 1, all of which parts for simplicity of illustration are omitted from Figs. 4 and 5.

It is usually advantageous to proportion or relate the motor elements to each other in such a way that the torque of the stopping motor is sufficient to overcome that of the driving motor in a two motor apparatus such as shown in Fig. 4 or, in the other apparatus illustrated, in such a way that the effect of the auxiliary windings in series with the positioned lamp is greater than required to stop the lamp-changing movement, by such a margin that the teeth of the ratchet which prevents backward driving of the lamp carrier are brought into contact with the stopping pawl.

The association of one of the motor windings with the lamp circuit in series with the positioned lamp will usually and most desirably be by a direct connection in the circuit as shown in the drawings rather than by an inductive connection. The winding will obviously be electrically associated with the lamp circuit in either case.

What is claimed is:

1. In a lamp changing apparatus, a plurality of lamps, and means including an alternating current motor for moving said lamps successively into current-consuming position, said motor having a coil in series with the positioned lamp for preventing the motor from operating when normal current is flowing through the positioned lamp by substantially neutralizing a rotation-producing component of the magnetic field of the motor.

2. In a lamp changing apparatus, a carrier for a plurality of lamps movable for positioning the lamp successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, an alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means having a winding to create a forwardly rotating magnetic field and a winding in series with the positioned lamp to prevent rotation of said rotating magnetic field.

3. In a lamp changing apparatus, a lamp carrier for a plurality of lamps movable for pcsitioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and means including a rotary armature alternating current motor operative on failure of the positioned lamp to move said carrier to position another lamp, said motor having a coil connected in the lamp circuit in series with the positioned lamp which when normal current is flowing through the positioned lamp substantially neutralizes a rotation-producing component of the magnetic field of the motor and thereby prevents operation of the motor.

4. In a lamp changing apparatus, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means comprising two windings, one of said windings when no current is flowing in the other Winding causing continuous rotation whereby the carrier is moved to move the failed lamp out of operative position and a new lamp into operative position, and the other winding being electrically associated with the lamp circuit in series with the positioned lamp and tending when normal current is flowing through a positioned lamp to cause rotation in the opposite direction and thereby preventing the motor means from operating to move the positioned lamp out oi! position.

5, In lamp changing apparatus, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means comprising two windings, one of said windings when no current is flowing in the other winding causing continuous rotation whereby the carrier is moved to move the failed lamp out of operative position and a new lamp into operative position, and the other winding being connected in the lamp circuit in series with the positioned lamp and tending when normal current is flowing through a positioned lamp to cause rotation in the opposite direction and thereby preventing the motor means from operating to move the positioned lamp out of position; and means for preventing backward rotation of the motor.

6. In a lamp changing apparatus, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means being a shaded pole alternating current motor having opposed shading coils, one of which is electrically associated with the lamp circuit in series with the positioned lamp, whereby the motor is prevented from operating when normal current is flowing through a positioned lamp.

'7. In a lamp changing apparatus, a plurality of lamps, and means including an alternating current motor for moving said lamps successively into current-consuming position, said motor having opposed shading coils one of which is in series with the positioned lamp for preventing the motor from operating when normal current is flowing through the positioned lamp.

8. In a lamp changing apparatus, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means being a shaded pole alternating current motor having opposed shading coils, one of which is connected in the lamp circuit in series With the positioned lamp, whereby the motor is prevented from operating when normal current is flowing through a positioned lamp, and detent means for preventing backward rotation of the motor.

9. In an apparatus of the character described, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and means operative on failure of the positioned lamp to move the carrier to position another lamp, said means including an induction motor having opposed field coils one of which is connected in the lamp circuit in series with the positioned lamp, and tends when normal current is flowing through the positioned lamp to cause reverse rotation and thereby prevents the motor from operating.

10. In a lamp changing apparatus, a lamp carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and means including a rotary armature alternating current motor operative on failure of the positioned lamp to move said carrier to position another lamp, said motor having wound shading coils connected in a closed circuit in series with an adjustably variable resistance, and having other wound shading coils opposed to the first said shading coils and electrically associated with the lamp circuit in series with the positioned lamp for preventing the motor from operating when normal current is flowing through the positioned lamp by substantially neutralizing a rotationproducing component of the magnetic field of the motor.

11. In an apparatus of the character described, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, and alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means comprising two motors tending to produce rotation in opposite directions, one of which is the driving motor in a circuit independent of the lamp circuit and the other of which motors is a stopping motor and is electrically associated with the lamp circuit in series with the positioned lamp and tends when normal current is flowing through a positioned lamp to cause rotation in the opposite direction and thereby prevents the driving motor from operating to move the positioned lamp out of position.

12. In an apparatus of the character described, a carrier for a plurality of lamps movable for positioning the lamps successively, a lamp circuit having terminals for connecting the positioned lamp in the circuit, alternating current motor means for moving the carrier on failure of the positioned lamp to position another lamp, said motor means comprising two induction motors tending to produce rotation in opposite directions, one of which is the driving motor in a circuit independent of the lamp circuit and the other of which motors is a stopping motor and is connected in the lamp circuit in series with the positioned lamp, whereby the driving motor is prevented from operating to move the lamp carrier when normal current is flowing through a positioned lamp, and detent means for preventing backward rotation of the driving motor.

JOHN R. MacKAY. 

